The invention relates generally to the field of industrial metrology and, in particular, to model-based measurement techniques using multiple views.
Measurement of objects is of vital importance in manufacturing and repair industries. Various types of measurement systems, such as computed tomography (CT), coordinate measuring machines (CMM), laser-based profilometry, and infrared, are used for industrial inspection. For example, these measurement systems may be used for measuring dimensions or for identifying defects in manufactured parts, such as tubes. Unfortunately, many of these measurement systems are costly, slow to produce, bulky, application specific, and require high maintenance. For example, different gauges are often required for different tubes. Also, in many applications the tubes considered are smooth surfaces without texture or fiducial markings, and therefore current techniques that rely on point correspondences cannot be employed, as the accuracy level is lower than acceptable. As the manufacturing tolerances become tighter, there is a corresponding increase in the demands for metrology techniques for maintaining the tolerances. The need for quality and performance testing has become an integral part of the production or manufacturing process.
Accordingly, a need exists for a measurement technique that is relatively inexpensive, versatile and programmable for different applications and that requires low maintenance.